– remove the bearings from the EFE front wheel, and take the tube which is in between them. Do the same with the GSX-R one.
– you will find out the EFE one is 16mm longer than the GSX-R one. It needs shortening 16mm.
– buy some bearings which fit in the GSX-R wheel and on the EFE spindle. I don’t remember exactly the sizes, but you need bearings with the ID of the EFE ones, and the OD and width of the GSX-R ones. They were off the shelf in the local bearings shop.
– the tubes in the bottoms of the EFE forks are now too short. Make some new ones which are 8mm (each) longer.
– the EFE speedo drive will fit after a little bit of material has been removed. Offer it up on the GSX-R wheel and you’ll see exactly where.

And now, with that nice 3-spoke wheel, it would be a shame not to upgrade the brakes as well.
The Slingshot Nissin 4-pots, and the later GSX-R models’ Tokico 4- and 6-pots all fit on the EFE forks, 90mm spacing between the bolts. But the Slingshot discs are too large.
Now Suzuki had thought about this and launched the GSX600F in the late eighties, this bike has brake discs that fit perfectly on the GSX-R wheel and are small enough to accept the more modern calipers when mounted in the EFE forks. All it needs is some small rings to space out the calipers a bit towards eachother.
Use the EFE caliper mounting bolts, they are longer than the GSX-R ones.

Below are drawings of engine mounts to fit an early air-cooled GSX (round frame tubes) or EFE (square frame tubes) with a GSX-R engine. Both place the engine in the middle which is aesthetically best but may cause some problems with the exhaust headers interfering with the frame downtubes, which can be solved by using spacers or modifying the headers if necessary.Engine mounts for a GSX1100 frame to take a GSX-R engine.By “jonboy”

A Katana with the above engine mounts installed…

Engine mounts for a GSX1100EFE (GS1150) to take a GSX-R engine.
By “GJG”

Below are drawings from the engine mounts, as I used them a few years back. I built at least two EFE’s using these plates. They mount the engine pretty straightforward, like in the Katana I send you pics from a few months back. I also included the cutting contours in .dxf format, that could straight be fed into a laser.

PL-107 and 108: These should be welded in with the engine or cases in place, mounted with the previous mentioned plates. PL-108 is a bit long, and could do with a brace, taking sideward loads to the cross tube from the shock. The stock plate should be removed. The lower cross tube in the frame will need some cleaning up and removing of the stock lower rear plates, before taking PL-107.

PL-110 and 111: These make the removable, welded upper rear engine mount taking loads to the stock bolt holes/bushings welded into the side of the frame.

First you remove the cover from the bike ofcourse, and then you degrease it very thoroughly.

As with all cracks in every material you need to drill small holes at the end of the cracks. Do not drill exactly at the point where the visible crack stops because underneath the surface the crack already had gone further. So plot an imaginative line in the extent of the crack and drill the hole along that line a few millimeters from the end of the visible crack.

I used a Dremel tool, but you can use a normal drill with a grinding stone (though due to it’s weight it’s harder to control) to dig a trench along the crack.
Dig as deep until you’re almost coming trough on the other side. This will make it very easy to fill it with epoxy.

Clean the other (in)side using emery paper or a Dremel tool to make sure the epoxy will attach itself well.

Then you clean and degrease the cover very thoroughly and warm it up by laying it on a heat source like a radiator or geyser.

While the case is heating up we prepare the metal epoxy. I use “Bison” metal epoxy but I guess any well known brand metal epoxy will do just fine. Just follow the instructions that came with it carefully and be sure to mix it very thoroughly. As with all two-component substances mixing it thoroughly is most important, so don’t rush it!

When the epoxy is ready apply it to the cover. Make sure you push the cracks full of epoxy so no air bubbles are left in them. If you dug them out deep enough epoxy will come out on the others side.
Your cover will have a very large flat spot so be sure to apply enough material, better too much than too little.
Apply some epoxy to the inside too but it hasn’t have to be much, just enough to make it smooth.

Then you leave it to dry on a heat source, at least for 12h untill the epoxy has become very hard. It hasn’t got the same mechanical properties as aluminium though, more like a hard plastic.

Now you can file/sand it into shape and spray paint the cover (you didn’t intend to polish it, now would ya? 😉

Well, there you are… a good as new engine cover, ready to last untill the next crash!